The Snow White and the Huntsman actor will play Finnick Odair in the upcoming sequel.
The British star had been rumoured to be appearing in the film since July, but Lionsgate has now confirmed the casting.
In Suzanne Collins's best-selling novels, Finnick is one of the main new characters in Catching Fire. He is a former winner of 'The Hunger Games', and is forced to return to the battlefield with other former champions including Katniss Everdeen (Jennifer Lawrence).
Finnick is known for his trident skills, and became a celebrity in the Capitol thanks to his charm and good looks.
Claflin has previously starred in Pirates of the Caribbean: On Stranger Tides and the TV series White Heat.
He joins the likes of Philip Seymour Hoffman, Jena Malone and Amanda Plummer as one of the new additions to the cast.
The Hunger Games: Catching Fire will be released on November 22, 2013.
In pictures - the cast of Catching Fire:
Copyright: PA Images Thomas Padilla/AP